These new kernel packages contain fixes for the three security issues described below as well as an important fix for a problem that could lead to data corruption on x86-architecture SMP systems with greater than 4GB of memory through heavy usage of multi-threaded applications.

A flaw between execve() syscall handling and core dumping of ELF-format executables allowed local unprivileged users to cause a denial of service (system crash) or possibly gain privileges. The Common Vulnerabilities and Exposures project has assigned the name CAN-2005-1263 to this issue.

A flaw in shared memory locking allowed local unprivileged users to lock and unlock regions of shared memory segments they did not own (CAN-2005-0176).

A flaw in the locking of SysV IPC shared memory regions allowed local unprivileged users to bypass their RLIMIT_MEMLOCK resource limit (CAN-2004-0491).

Note: The kernel-unsupported package contains various drivers and modules that are unsupported and therefore might contain security problems that have not been addressed.

All Red Hat Enterprise Linux 3 users are advised to upgrade their kernels to the packages associated with their machine architectures and configurations as listed in this erratum.

Please also consult the RHEL3 Update 5 advisory RHSA-2005:294 for the complete list of features added and bugs fixed in U5, which was released only a week prior to this security update.

4. Solution:

Before applying this update, make sure that all previously released errata relevant to your system have been applied. Use Red Hat Network to download and update your packages. To launch the Red Hat Update Agent, use the following command:

up2date

For information on how to install packages manually, refer to the following Web page for the System Administration or Customization guide specific to your system: